Even with multiple acclaimed performances and three Oscar nominations to his name, actor Joaquin Phoenix is yet to bag an Academy Award. However, that could all be set to change courtesy of his title role in Joker.

Pitched as a grounded study of mental illness that's separate from the DC Universe series of films, Joker is building serious Oscar buzz. This reached fever pitch over the weekend when the movie hosted its world premiere at the Venice Film Festival, gathering laudatory reviews (and an eight-minute standing ovation) in the process.

Phoenix stars as Arthur Fleck, a struggling stand-up comic who is marginalised and brutalised during his life in Gotham City. The tragedy of Fleck's life hastens his transformation into the Clown Prince of Crime, with the film's excellent supporting cast including Robert De Niro and Zazie Beetz.

The movie is directed by Todd Phillips, best known for directing crude comedies like the Hangover trilogy. He's been open in citing his debt to director Martin Scorsese – the psychological madness of Joker is said to derive influence from the latter's Mean Streets, Taxi Driver and The King of Comedy.

The consistent element in all of the reviews is the praise afforded to Phoenix's performance. The movie currently stands at 88% on Rotten Tomatoes where it's described as "a chillingly plausible origin story that serves as a brilliant showcase for its star -- and a dark evolution for comics-inspired cinema".

"This is a truly nightmarish vision of late-era capitalism – arguably the best social horror film since Get Out – and Joaquin Phoenix is magnetic in it," raves Time Out's Phil De Semylen in his five-star review. "This character isn’t just a makeup-smeared facsimile of Robert De Niro’s traumatised [Taxi Driver] veteran. He’s the product of a society that feels painfully current. He needs help, but there’s no help out there for him."

"A dazzlingly disturbed psycho morality play," is how Variety's Own Gleiberman describes the film, "one that speaks to the age of incels and mass shooters and no-hope politics, of the kind of hate that emerges from crushed dreams...

"Phoenix’s performance is astonishing. He appears to have lost weight for the role, so that his ribs and shoulder blades protrude, and the leanness burns his face down to its expressive essence: black eyebrows, sallow cheeks sunk in gloom, a mouth so rubbery it seems to be snarking at the very notion of expression, all set off by a greasy mop of hair. Phoenix is playing a geek with an unhinged mind, yet he’s so controlled that he’s mesmerising. He stays true to the desperate logic of Arthur’s unhappiness."

The Hollywood Reporter's David Rooney describes it thusly: "Built around a credible spiral from lonely outsider to deranged killer, it's as much a neo-noir psychological character study grounded in urban alienation and styled after Taxi Driver as a rise-of-the-supervillain portrait.

"It's arguably the best Batman-adjacent movie since The Dark Knight and Warner should see mighty box office numbers to reflect that. The must-see factor of Phoenix's riveting performance alone — it's both unsettling and weirdly affecting — will be significant."

"Phoenix inhabits Arthur: having lost weight for the role, he looks thin, frail, hungry," writes Empire's Terri White. "Shadows carve out his exposed bones. His physicality is precise — the way he moves, shuffles, runs, sits, smokes, shrinks. His usual intensity is on full display and it’s captivating, even overwhelming in moments. Comparing him to Heath Ledger and Jack Nicholson feels like a nonsense: this is a Joker we’ve never seen — in many respects it isn’t the Joker, it’s Arthur."

"What a gloriously daring and explosive film Joker is," raves The Guardian's Xan Brooks. "It’s a tale that’s almost as twisted as the man at its centre, bulging with ideas and pitching towards anarchy.

"Having brazenly plundered the films of Scorsese, Phillips fashions stolen ingredients into something new, so that what began as a gleeful cosplay session turns progressively more dangerous – and somehow more relevant, too. Gotham City is aflame and they’re rioting on the streets. And a rough beast is slouching towards the TV studio to be born."

Of course, there are dissenting voices. Little White Lies critic David Jenkins disparages the movie as "feeble posturing, asinine pop psychology and political analysis charged with all the cynicism of a mollycoddled teen dropout in fake Oakleys and a home customised Linkin Park tee".

You can cast your own verdict on Joker and Phoenix's Oscar chances when Joker is released on 4th October. Don't forget to tweet us your thoughts @Cineworld.